CN110831830B

CN110831830B - Brake control device

Info

Publication number: CN110831830B
Application number: CN201880042578.XA
Authority: CN
Inventors: 浅野智孝; 山本贵之; 石田康人; 小林达史; 西胁邦博
Original assignee: Advics Co Ltd
Current assignee: Advics Co Ltd
Priority date: 2017-06-28
Filing date: 2018-06-25
Publication date: 2021-08-17
Anticipated expiration: 2038-06-25
Also published as: JP6747388B2; WO2019004138A1; US20200198603A1; JP2019006335A; CN110831830A

Abstract

The brake control device of the invention comprises: a1 st control unit 6 that controls a1 st pressurizing mechanism BF1 capable of pressurizing the brake fluid in one of a plurality of set pressurizing modes; and a2 nd control unit 8 provided separately from the 1 st pressurizing mechanism BF1 and configured to control the 2 nd pressurizing mechanism 5 capable of pressurizing the brake fluid pressurized by the 1 st pressurizing mechanism BF1, wherein the 1 st control unit 6 and the 2 nd control unit 8 perform coordinated control based on control information, wherein the brake control device is provided with a pattern estimating unit 82 configured to estimate a current pressurizing pattern set at the 1 st pressurizing mechanism BF1 when transmission of the control information is interrupted, and the 2 nd control unit 8 is provided with a specific control unit 83, and wherein the specific control unit 83 controls the 2 nd pressurizing mechanism 5 in accordance with the pressurizing pattern estimated by the pattern estimating unit 82 in a state where transmission of the control information is interrupted.

Description

Brake control device

Technical Field

The present invention relates to a brake control device that controls 2 pressurizing mechanisms.

Background

The brake control device is provided with a1 st control unit for controlling one of the 2 pressurizing mechanisms and a2 nd control unit for controlling the other pressurizing mechanism, and performs cooperative control of both mechanisms by communication between both control units. In the conventional apparatus, when communication between the two control units is interrupted, each control unit assumes that the pressurizing mechanism of the other control unit is not in a normal state, and sets a high target deceleration. Therefore, when communication is interrupted, if both the pressurizing mechanisms are in a normal state, the braking force may become excessive.

In the brake control device described in, for example, international publication No. 2016/136671, the 2 nd control unit is configured to execute a backup control for pressurizing the brake fluid in the wheel cylinder when communication between the two control units is interrupted, and to reduce the amount of pressurization to the wheel cylinder when the pressure of the master cylinder exceeds a predetermined value in the backup control. This can suppress an excessive braking force.

Patent document 1: international publication No. 2016/136671

However, in the above-described brake control device, since the determination as to whether or not to decrease the amount of pressurization of the hydraulic control mechanism is made only on the basis of the pressure of the master cylinder, the amount of pressurization is not changed until a pressure of the master cylinder that is high to some extent is detected. That is, the braking force may become excessive until the driver's braking operation becomes large to some extent.

Disclosure of Invention

The present invention has been made in view of such circumstances, and an object thereof is to provide a brake control device capable of accurately suppressing an excessive braking force.

The brake control device of the invention comprises: a1 st control unit that controls a1 st pressurizing mechanism capable of pressurizing a brake fluid in one of a plurality of set pressurizing modes; a2 nd control unit which is provided separately from the 1 st pressurizing mechanism and controls a2 nd pressurizing mechanism capable of pressurizing the brake fluid pressurized by the 1 st pressurizing mechanism; and a communication line for transmitting control information between the 1 st control unit and the 2 nd control unit, wherein the 1 st control unit and the 2 nd control unit perform cooperative control based on the control information, wherein the brake control device includes a mode estimation unit that estimates a current pressurization mode set at the 1 st pressurization mechanism when transmission of the control information between the 1 st control unit and the 2 nd control unit is interrupted, and the 2 nd control unit includes a specific control unit that controls the 2 nd pressurization mechanism based on the pressurization mode estimated by the mode estimation unit in a state where transmission of the control information is interrupted.

According to the present invention, when the transmission of information between the two control units is interrupted, the mode estimating unit estimates the current pressurizing mode of the 1 st pressurizing mechanism, and the specific control unit controls the 2 nd pressurizing mechanism based on the estimated pressurizing mode. Therefore, the control according to the state of the 1 st pressurizing mechanism can be executed at an early stage, and as a result, the excessive braking force can be suppressed with high accuracy.

Drawings

Fig. 1 is a configuration diagram of a vehicle brake device according to a first embodiment.

Fig. 2 is a structural diagram of the regulator of the first embodiment.

Fig. 3 is a structural view of the actuator of the first embodiment.

Fig. 4 is an explanatory diagram for explaining the pattern estimation of the first embodiment.

Fig. 5 is a flowchart showing the flow of specific control of the first embodiment.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent portions are denoted by the same reference numerals in the drawings. In the second and third embodiments, the description of the first embodiment and the drawings can be referred to.

< first embodiment >

As shown in fig. 1, the vehicle brake device includes a hydraulic braking force generation device BF, a1 st control unit 6, and a2 nd control unit 8. The 1 st control unit 6 and the 2 nd control unit 8 constitute a brake control device 100. The hydraulic braking force generation device BF includes a master cylinder 1, a reaction force generation device 2, a1 st control valve 22, a2 nd control valve 23, a servo pressure generation device (force multiplying mechanism) 4, an actuator (corresponding to a "2 nd pressurizing mechanism") 5, wheel cylinders 541 to 544, and various sensors 71 to 77.

The master cylinder 1, the 1 st control valve 22, the 2 nd control valve 23, and the servo pressure generating device 4 mainly constitute an upstream side pressurizing mechanism (corresponding to the "1 st pressurizing mechanism") BF1, which is an upstream side (main pressure) pressurizing mechanism. The actuator 5 constitutes a downstream side pressurizing mechanism which is a pressurizing mechanism on the downstream side (wheel pressure). That is, the hydraulic braking force generation device BF includes the upstream side pressurizing mechanism BF1 and the actuator 5 as the downstream side pressurizing mechanism.

The master cylinder 1 is a portion for supplying the operating fluid to the actuator 5 in accordance with the operation amount of a brake pedal (corresponding to a "brake operating member") 10, and is configured by a master cylinder 11, a cover cylinder 12, an input piston 13, a1 st master piston 14, a2 nd master piston 15, and the like. The brake pedal 10 may be a brake operation member that can be operated by the driver.

The master cylinder 11 is a substantially cylindrical case closed at the front and opened at the rear. An inner wall portion 111 protruding inward in a flange shape is provided in the rear of the inner peripheral side of the master cylinder 11. The center of the inner wall 111 is a through hole 111a penetrating in the front-rear direction. Further, small diameter portions 112 (rear) and 113 (front) having a slightly smaller inner diameter are provided in the master cylinder 11 forward of the inner wall portion 111. That is, the small diameter portions 112 and 113 protrude inward from the inner peripheral surface of the master cylinder 11 in an annular shape. Inside the master cylinder 11, the 1 st master piston 14 is mounted to be movable in the axial direction in sliding contact with the small-diameter portion 112. Similarly, the 2 nd master piston 15 is mounted to be movable in the axial direction in sliding contact with the small-diameter portion 113.

The cover cylinder 12 includes a substantially cylindrical cylinder portion 121, a bellows-shaped cover 122, and a cup-shaped compression spring 123. The cylinder portion 121 is disposed on the rear end side of the master cylinder 11, and is coaxially fitted into a rear opening of the master cylinder 11. The inner diameter of the front portion 121a of the cylinder part 121 is larger than the inner diameter of the through hole 111a of the inner wall 111. The inner diameter of the rear portion 121b of the cylinder part 121 is smaller than the inner diameter of the front portion 121 a.

The dust-proof shield 122 is extendable and retractable in the front-rear direction in a bellows shape, and is assembled so that its front side contacts the rear end side opening of the cylinder portion 121. A through-hole 122a is formed in the rear center of the shroud 122. The compression spring 123 is a spiral biasing member disposed around the shroud 122, and has a front side abutting against the rear end of the master cylinder 11 and a rear side reduced in diameter so as to approach the through hole 122a of the shroud 122. The rear end of the shroud 122 and the rear end of the compression spring 123 are coupled to the operating rod 10 a. The compression spring 123 biases the operating lever 10a rearward.

The input piston 13 is a piston that slides within the cover cylinder 12 in accordance with the operation of the brake pedal 10. The input piston 13 is a bottomed substantially cylindrical piston having a bottom surface on the front and an opening on the rear. The bottom wall 131 constituting the bottom surface of the input piston 13 has a larger diameter than other portions of the input piston 13. The input piston 13 is disposed to be slidable in the axial direction and liquid-tight at the rear portion 121b of the cylinder block 121, and the bottom wall 131 is disposed to enter the inner circumferential side of the front portion 121a of the cylinder block 121.

An operating rod 10a that is interlocked with the brake pedal 10 is fitted inside the input piston 13. The pivot 10b at the tip of the operating lever 10a is configured to be able to push the input piston 13 forward. The rear end of the operating rod 10a protrudes to the outside through the opening on the rear side of the input piston 13 and the through hole 122a of the shroud 122, and is connected to the brake pedal 10. When the brake pedal 10 is depressed, the operating lever 10a pushes the shroud 122 and the compression spring 123 in the axial direction to advance them. As the operation rod 10a advances, the input piston 13 also advances in conjunction therewith.

The 1 st master piston 14 is slidably fitted in the axial direction in an inner wall portion 111 of the master cylinder 11. The 1 st master piston 14 is formed by integrating a pressurizing cylinder portion 141, a flange portion 142, and a projection portion 143 in this order from the front side. The pressurizing cylinder portion 141 is formed in a substantially cylindrical shape with an opening at the front and a bottom, has a gap with the inner circumferential surface of the master cylinder 11, and is in sliding contact with the small diameter portion 112. A coil spring-like urging member 144 is mounted in the internal space of the pressure cylinder portion 141 between the 2 nd main piston 15 and the pressure cylinder portion 141. The 1 st main piston 14 is biased rearward by the biasing member 144. In other words, the 1 st master piston 14 is biased toward the set initial position by the biasing member 144.

The flange portion 142 has a larger diameter than the pressure cylinder portion 141 and is in sliding contact with the inner peripheral surface of the master cylinder 11. The projection 143 has a smaller diameter than the flange 142 and is arranged to slide liquid-tightly with the through hole 111a of the inner wall 111. The rear end of the projection 143 projects into the inner space of the cylinder part 121 through the through hole 111a, and is separated from the inner circumferential surface of the cylinder part 121. The rear end surface of the projection 143 is spaced apart from the bottom wall 131 of the input piston 13, and the distance of separation can be varied.

Here, "1 st master chamber 1D" is defined by the inner peripheral surface of the master cylinder 11, the front side of the pressurizing cylinder portion 141 of the 1 st master piston 14, and the rear side of the 2 nd master piston 15. Further, a rear chamber rearward of the 1 st master chamber 1D is defined by the inner peripheral surface (inner peripheral portion) of the master cylinder 11, the front surfaces of the small diameter portion 112 and the inner wall portion 111, and the outer peripheral surface of the 1 st master piston 14. The front end portion and the rear end portion of the flange portion 142 of the 1 st master piston 14 divide the rear chamber region into the front and rear sides, and the front side is divided into the "2 nd hydraulic chamber 1C", and the rear side is divided into the "servo chamber 1A". The 2 nd hydraulic chamber 1C decreases in volume due to the forward movement of the 1 st master piston 14, and increases in volume due to the backward movement of the 1 st master piston 14. The "1 st hydraulic chamber 1B" is defined by the inner peripheral portion of the master cylinder 11, the rear surface of the inner wall portion 111, the inner peripheral surface (inner peripheral portion) of the front portion 121a of the cylinder portion 121, the projection 143 (rear end portion) of the 1 st master piston 14, and the front end portion of the input piston 13.

The 2 nd master piston 15 is disposed in the master cylinder 11 on the front side of the 1 st master piston 14 so as to be movable in the axial direction while being in sliding contact with the small diameter portion 113. The 2 nd main piston 15 is formed by integrating a cylindrical pressurizing cylinder 151 having an opening at the front and a bottom wall 152 closing the rear side of the pressurizing cylinder 151. The bottom wall 152 supports the urging member 144 between the 1 st master piston 14 and the bottom wall. A coil spring-like urging member 153 is mounted in the internal space of the pressure cylinder portion 151 between the closed inner bottom surface 111d of the master cylinder 11 and the member. The 2 nd main piston 15 is biased rearward by the biasing member 153. In other words, the 2 nd master piston 15 is biased toward the set initial position by the biasing member 153. The "2 nd master chamber 1E" is defined by the inner peripheral surface of the master cylinder 11, the inner bottom surface 111d, and the 2 nd master piston 15.

The master cylinder 1 is formed with ports 11a to 11i that communicate the inside with the outside. The through hole 11a is formed in the master cylinder 11 rearward of the inner wall portion 111. The through hole 11b is formed to face the through hole 11a at the same position as the through hole 11a in the axial direction. The port 11a and the port 11b communicate via an annular space between the inner peripheral surface of the master cylinder 11 and the outer peripheral surface of the cylinder portion 121. The ports 11a and 11b are connected to the pipe 161 and to the reservoir 171 (low pressure source).

The port 11B communicates with the 1 st hydraulic chamber 1B through a passage 18 formed in the cylinder portion 121 and the input piston 13. When the input piston 13 advances, the passage 18 is blocked, and the 1 st hydraulic chamber 1B is thereby blocked from the reservoir 171. The port 11c is formed rearward of the inner wall portion 111 and forward of the port 11a, and communicates the 1 st hydraulic chamber 1B with the pipe 162. The port 11d is formed in front of the port 11c, and communicates the servo chamber 1A with the pipe 163. The port 11e is formed ahead of the port 11d, and communicates the 2 nd hydraulic chamber 1C with the pipe 164.

The port 11f is formed between the seal members G1, G2 at the small diameter portion 112, and communicates the reservoir 172 with the interior of the master cylinder 11. The port 11f communicates with the 1 st master chamber 1D via a passage 145 formed in the 1 st master piston 14. The passage 145 is formed at a position where the port 11f is blocked from the 1 st master chamber 1D when the 1 st master piston 14 advances. The port 11g is formed in front of the port 11f, and communicates the 1 st master chamber 1D with the pipe line 31.

The port 11h is formed between the two seal members G3, G4 at the small diameter portion 113, and communicates the reservoir 173 with the interior of the master cylinder 11. The port 11h communicates with the 2 nd master chamber 1E via a passage 154 formed in the pressurizing cylinder 151 of the 2 nd master piston 15. The passage 154 is formed at a position where the port 11h and the 2 nd master chamber 1E are blocked when the 2 nd master piston 15 advances. The port 11i is formed in front of the port 11h, and communicates the 2 nd main chamber 1E with the pipe line 32.

Further, a seal member such as an O-ring is appropriately disposed in the master cylinder 1. The seal members G1, G2 are disposed at the small diameter portion 112, and liquid-tightly contact the outer peripheral surface of the 1 st master piston 14. Similarly, the seal members G3, G4 are disposed at the small diameter portion 113, and liquid-tightly abut against the outer peripheral surface of the 2 nd master piston 15. Further, seal members G5 and G6 are also disposed between the input piston 13 and the cylinder block 121.

The stroke sensor 71 is a sensor that detects the amount of operation (stroke) of the brake pedal 10 by the driver, and transmits detection signals to the 1 st control unit 6 and the 2 nd control unit 8. The brake stop switch 72 is a switch for detecting the presence or absence of the operation of the brake pedal 10 by the driver with a 2-value signal, and transmits the detection signal to the 1 st control unit 6.

The reaction force generation device 2 is a device that generates a reaction force against an operation force when the brake pedal 10 is operated, and is configured mainly from a stroke simulator 21. The stroke simulator 21 generates reaction force hydraulic pressures in the 1 st hydraulic chamber 1B and the 2 nd hydraulic chamber 1C in accordance with an operation of the brake pedal 10. The piston 212 is slidably fitted to the cylinder 211 to constitute the stroke simulator 21. The piston 212 is biased rearward by a compression spring 213, and a reaction force hydraulic chamber 214 is formed on the rear side of the piston 212. The reaction force hydraulic chamber 214 is connected to the 2 nd hydraulic chamber 1C via the pipe 164 and the port 11e, and the reaction force hydraulic chamber 214 is connected to the 1 st control valve 22 and the 2 nd control valve 23 via the pipe 164.

The 1 st control valve 22 is a solenoid valve having a structure that is closed in a non-energized state, and is controlled to open and close by the 1 st control unit 6. The 1 st control valve 22 is connected between the pipe 164 and the pipe 162. Here, the pipe 164 is connected to the 2 nd hydraulic chamber 1C through the port 11e, and the pipe 162 is connected to the 1 st hydraulic chamber 1B through the port 11C. When the 1 st control valve 22 is opened, the 1 st hydraulic chamber 1B is opened, and when the 1 st control valve 22 is closed, the 1 st hydraulic chamber 1B is closed. Therefore, the pipe 164 and the pipe 162 are provided to communicate the 1 st hydraulic chamber 1B and the 2 nd hydraulic chamber 1C.

The 1 st control valve 22 is closed in a non-energized state where it is not energized, and at this time, the 1 st hydraulic chamber 1B and the 2 nd hydraulic chamber 1C are blocked. As a result, the 1 st hydraulic chamber 1B is closed and the destination of the hydraulic fluid disappears, and the input piston 13 and the 1 st master piston 14 are interlocked with each other while maintaining a constant separation distance. In addition, the 1 st control valve 22 is opened in the energized state in which the 1 st hydraulic chamber 1B and the 2 nd hydraulic chamber 1C are communicated with each other. Thus, the change in the volumes of the 1 st hydraulic chamber 1B and the 2 nd hydraulic chamber 1C accompanying the advance and retreat of the 1 st master piston 14 is absorbed by the movement of the working fluid.

The pressure sensor 73 is a sensor that detects the reaction hydraulic pressures of the 2 nd hydraulic chamber 1C and the 1 st hydraulic chamber 1B, and is connected to the pipe 164. The pressure sensor 73 detects the pressure of the 2 nd hydraulic chamber 1C when the 1 st control valve 22 is in the closed state, and also detects the pressure of the 1 st hydraulic chamber 1B that communicates when the 1 st control valve 22 is in the open state. The pressure sensor 73 transmits a detection signal to the 1 st control unit 6.

The 2 nd control valve 23 is a solenoid valve having a structure that opens in a non-energized state, and is controlled to open and close by the 1 st control unit 6. The 2 nd control valve 23 is connected between the pipe 164 and the pipe 161. Here, the pipe 164 is communicated with the 2 nd hydraulic chamber 1C through the port 11e, and the pipe 161 is communicated with the reservoir 171 through the port 11 a. Therefore, the 2 nd control valve 23 communicates between the 2 nd hydraulic chamber 1C and the accumulator 171 in the non-energized state without generating the reaction hydraulic pressure, and is blocked in the energized state to generate the reaction hydraulic pressure.

The servo pressure generating device 4 is constituted by a pressure reducing valve 41, a pressure increasing valve 42, a pressure supply portion 43, a regulator 44, and the like. The pressure reducing valve 41 is a normally open type solenoid valve (normally open valve) that is opened in a non-energized state, and the flow rate (or pressure) is controlled by the 1 st control unit 6. One side of the pressure reducing valve 41 is connected to the pipe 161 via a pipe 411, and the other side of the pressure reducing valve 41 is connected to a pipe 413. That is, one of the pressure reducing valves 41 communicates with the reservoir 171 via the

pipes

411 and 161 and the ports 11a and 11 b. The pressure reducing valve 41 closes to prevent the working fluid from flowing out of the 1 st guide chamber 4D described later. The reservoir 171 and the reservoir 434 are not shown but communicate with each other. The reservoir 171 may be the same reservoir as the reservoir 434.

The pressure increasing valve 42 is a normally closed electromagnetic valve (normally closed valve) that is closed in a non-energized state, and the flow rate (or pressure) is controlled by the 1 st control unit 6. One of the pressure increasing valves 42 is connected to a pipe 421, and the other of the pressure increasing valves 42 is connected to a pipe 422. The pressure supply unit 43 is a part that mainly supplies the high-pressure working fluid to the regulator 44. The pressure supply unit 43 includes an accumulator (high-pressure source) 431, a hydraulic pump 432, a motor 433, an accumulator 434, and the like.

The accumulator 431 is a tank for accumulating the high-pressure working fluid. The accumulator 431 is connected to the regulator 44 and the hydraulic pump 432 through a pipe 431 a. The hydraulic pump 432 is driven by a motor 433, and pumps the hydraulic fluid stored in a reservoir 434 to an accumulator 431. The pressure sensor 75 provided in the pipe 431a detects the accumulator hydraulic pressure of the accumulator 431, and transmits a detection signal to the 1 st control unit 6. The accumulator hydraulic pressure is related to the amount of the working fluid accumulated in the accumulator 431.

When the pressure sensor 75 detects that the accumulator hydraulic pressure has decreased to a predetermined value or less, the motor 433 is driven in accordance with a command from the 1 st control unit 6. As a result, the hydraulic pump 432 feeds the hydraulic fluid to the accumulator 431, and the accumulator hydraulic pressure is returned to a predetermined value or more.

As shown in fig. 2, the regulator 44 includes a cylinder 441, a ball valve 442, an urging portion 443, a valve seat portion 444, a control piston 445, a sub-piston 446, and the like. The cylinder 441 includes a substantially bottomed cylindrical cylinder case 441a having a bottom surface on one side (right side in the drawing), and a cover member 441b that closes an opening (left side in the drawing) of the cylinder case 441 a. The cylinder case 441a is formed with a plurality of ports 4a to 4h that communicate the inside with the outside. The cover member 441b is also formed in a substantially bottomed cylindrical shape, and each through opening is formed in each portion of the cylindrical portion facing the plurality of through openings 4a to 4 h.

Port 4a is connected to pipe 431 a. Port 4b is connected to pipe 422. The port 4c is connected to the pipe 163. The pipe 163 connects the servo chamber 1A and the port 4 c. Port 4d is connected to reservoir 434 via pipe 414. Port 4e is connected to a pipe 424, and further to a pipe 422 via a relief valve 423. The port 4f is connected to the pipe 413. Port 4g is connected to pipe 421. The port 4h is connected to a pipe 311 branched from the pipe 31.

The ball valve 442 is a ball-type valve and is disposed on the bottom surface side (hereinafter, also referred to as the cylinder bottom surface side) of the cylinder case 441a inside the cylinder 441. The biasing portion 443 is a spring member that biases the ball valve 442 toward the opening side of the cylinder case 441a (hereinafter, also referred to as the cylinder opening side), and is provided on the bottom surface of the cylinder case 441 a. The valve seat portion 444 is a wall member provided on the inner peripheral surface of the cylinder case 441a, and defines a cylinder opening side and a cylinder bottom surface side. A through passage 444a is formed in the center of the seat portion 444 to communicate the partitioned cylinder opening side with the cylinder bottom surface side. The seat portion 444 holds the ball valve 442 from the cylinder opening side in a shape such that the biased ball valve 442 closes the through passage 444 a. A seat surface 444b, with which the ball valve 442 can be detachably seated (abutted), is formed at an opening portion on the cylinder bottom surface side of the through passage 444 a.

A space defined by the ball valve 442, the biasing portion 443, the seat portion 444, and the inner peripheral surface of the cylinder housing 441a on the cylinder bottom surface side is defined as "1 st chamber 4A". The 1 st chamber 4A is filled with the working liquid, and is connected to the pipe 431a through the port 4A and the pipe 422 through the port 4 b.

The control piston 445 is composed of a substantially cylindrical main body portion 445a and a substantially cylindrical protruding portion 445b having a smaller diameter than the main body portion 445 a. In the cylinder 441, the main body portion 445a is disposed coaxially and liquid-tightly slidably in the axial direction on the cylinder opening side of the valve seat portion 444. The body 445a is biased toward the cylinder opening side by a biasing member, not shown. A passage 445c having both ends opened to the circumferential surface of the main body portion 445a and extending in the radial direction (vertical direction in the drawing) is formed substantially at the center of the main body portion 445a in the cylinder axial direction. A through hole 4d is formed in the inner peripheral surface of a part of the cylinder 441 corresponding to the opening position of the passage 445c, and is recessed in a concave shape. The space of the recess is defined as "3 rd chamber 4C".

The protruding portion 445b protrudes from the center of the cylinder bottom surface side end surface of the body portion 445a toward the cylinder bottom surface side. The diameter of the projection 445b is smaller than the passage 444a of the seat portion 444. The projection 445b is disposed coaxially with the penetration 444 a. The tip of the projection 445b is spaced apart from the ball valve 442 by a predetermined distance toward the cylinder opening side. The projection 445b is provided with a passage 445d extending in the cylinder axial direction and opening at the center of the cylinder bottom surface side end face of the projection 445 b. The passage 445d extends into the body 445a and is connected to the passage 445 c.

A space defined by the cylinder bottom surface side end surface of the main body portion 445a, the outer peripheral surface of the projection portion 445B, the inner peripheral surface of the cylinder 441, the seat portion 444, and the ball valve 442 is referred to as a "2 nd chamber 4B". The 2 nd chamber 4B communicates with the

ports

4d and 4e through the passages 445d and 445C and the 3 rd chamber 4C in a state where the projection 445B is not in contact with the ball valve 442.

The sub piston 446 is composed of a sub body portion 446a, a1 st projecting portion 446b, and a2 nd projecting portion 446 c. The sub body portion 446a is formed in a substantially cylindrical shape. In the cylinder 441, the sub body portion 446a is disposed on the cylinder opening side of the body portion 445a so as to be coaxially slidable in the axial direction in a liquid-tight manner. Further, a damper mechanism may be provided at an end portion of the sub piston 446 on the cylinder bottom surface side.

The 1 st projection 446b is substantially cylindrical in shape having a smaller diameter than the sub body portion 446a, and projects from the center of the cylinder bottom surface side end surface of the sub body portion 446 a. The 1 st projection 446b abuts on the cylinder opening side end surface of the body 445 a. The 2 nd projection 446c has the same shape as the 1 st projection 446b and projects from the center of the end surface of the sub body portion 446a on the cylinder opening side. The 2 nd projection 446c abuts the cover member 441 b.

A space defined by an end surface of the sub body portion 446a on the cylinder bottom surface side, an outer peripheral surface of the 1 st projection 446b, an end surface of the control piston 445 on the cylinder opening side, and an inner peripheral surface of the cylinder 441 is referred to as a "1 st guide chamber 4D". The 1 st guide chamber 4D is connected to the pressure reducing valve 41 via a port 4f and a pipe 413, and is connected to the pressure increasing valve 42 via a port 4g and a pipe 421.

On the other hand, a space defined by the end surface of the sub body portion 446a on the cylinder opening side, the outer peripheral surface of the 2 nd projecting portion 446c, the cover member 441b, and the inner peripheral surface of the cylinder 441 is referred to as a "2 nd guide chamber 4E". The 2 nd guide chamber 4E is communicated with the port 11g via the port 4h and the

conduits

311 and 31. The chambers 4A to 4E are filled with a working fluid. The pressure sensor 74 is a sensor for detecting the servo pressure supplied to the servo chamber 1A, and is connected to the pipe 163. The pressure sensor 74 transmits a detection signal to the 1 st control unit 6.

As described above, the regulator 44 is configured to have the control piston 445 driven by the difference between the force corresponding to the pressure of the 1 st guide chamber 4D (also referred to as "guide pressure") and the force corresponding to the servo pressure, and when the volume of the 1 st guide chamber 4D changes with the movement of the control piston 445, and the flow rate of the liquid flowing into and out of the 1 st guide chamber 4D increases, the amount of movement of the control piston 445 with respect to the position of the control piston 445 in a balanced state in which the force corresponding to the guide pressure and the force corresponding to the servo pressure are balanced increases, and the flow rate of the liquid flowing into and out of the servo chamber 1A increases. That is, the regulator 44 is configured such that a flow rate of the liquid corresponding to the differential pressure between the pilot pressure and the servo pressure flows into and out of the servo chamber 1A.

The actuator 5 is disposed between the 1 st master chamber 1D and the 2 nd master chamber 1E, which are generated by the master pressure, and the wheel cylinders 541 to 544. The actuator 5 is connected to the 1 st master chamber 1D through a pipe 31, and the actuator 5 is connected to the 2 nd master chamber 1E through a pipe 32. The actuator 5 is a device that adjusts the hydraulic pressure (wheel pressure) of the wheel cylinders 541 to 544 in accordance with the instruction of the 2 nd control unit 8. The actuator 5 executes pressurization control, pressure reduction control, and holding control for further pressurizing the brake fluid from the main pressure in accordance with the instruction of the 2 nd control unit 8. The actuator 5 performs a slip prevention control (ABS control), a slip prevention control (ESC control), or the like by combining these controls in accordance with a command from the 2 nd control unit 8.

Specifically, as shown in fig. 3, the actuator 5 includes a hydraulic circuit 5A and a motor 90. The hydraulic circuit 5A includes a1 st piping system 50a and a2 nd piping system 50 b. The 1 st piping system 50a is a system that controls the hydraulic pressure (wheel pressure) applied to the rear wheels Wrl, Wrr. The 2 nd piping system 50b is a system for controlling the hydraulic pressure (wheel pressure) applied to the front wheels Wfl, Wfr. Further, a wheel speed sensor 76 is provided for each wheel W. In the first embodiment, front and rear pipes are used.

The 1 st piping system 50a includes a main line a, a differential pressure control valve 51,

pressure increasing valves

52, 53, a pressure reducing line B,

pressure reducing valves

54, 55, a pressure regulating reservoir 56, a circulation line C, a pump 57, an auxiliary line D, an orifice portion 58, and a damper portion 59. In the description, the term "piping" may be replaced with, for example, a hydraulic passage, a flow path, an oil path, a passage, a pipe, or the like.

The main line a is a line connecting the line 32 and the wheel cylinders 541 and 524. The differential pressure control valve 51 is a solenoid valve provided in the main line a and controlling the main line a to be in a communicating state and a differential pressure state. The differential pressure state is a state in which the flow path is restricted by the valve, and is also referred to as a closed state. The differential pressure control valve 51 controls a differential pressure (hereinafter, also referred to as "first differential pressure") between the hydraulic pressure on the master cylinder 1 side and the hydraulic pressures on the

wheel cylinders

541 and 542 sides, centered on itself, based on a control current based on an instruction from the 2 nd control unit 8. In other words, the differential pressure control valve 51 is configured to be able to control the differential pressure between the hydraulic pressure in the portion of the main line a on the master cylinder 1 side and the hydraulic pressure in the portions of the main line a on the

wheel cylinders

541 and 542 sides.

The differential pressure control valve 51 is a normally open type that is brought into a communicating state in a non-energized state. The greater the control current applied to the differential pressure control valve 51, the greater the first differential pressure becomes. When the differential pressure control valve 51 is controlled to be in the differential pressure state and the pump 57 is driven, the hydraulic pressure on the

wheel cylinders

541 and 542 side becomes larger than the hydraulic pressure on the master cylinder 1 side by the control current. A check valve 51a is provided for the differential pressure control valve 51. The main line a branches into 2 lines a1, a2 at a branch point X on the downstream side of the differential pressure control valve 51 so as to correspond to the

wheel cylinders

541, 542.

The

pressure increase valves

52 and 53 are solenoid valves that are opened and closed by an instruction from the 2 nd control unit 8, and are normally open solenoid valves that are opened (communicated) in a non-energized state. The pressure increasing valve 52 is disposed on the conduit a1, and the pressure increasing valve 53 is disposed on the conduit a 2. The pressure-increasing

valves

52, 53 are opened in a non-energized state during pressure-increasing control to communicate the wheel cylinders 541 to 544 with the branch point X, and are energized to be closed during holding control and pressure-reducing control to block the wheel cylinders 541 to 544 from the branch point X.

The pressure-reducing conduit B is a conduit that connects between the pressure-increasing valve 52 and the

wheel cylinders

541, 542 in the conduit a1 and the pressure-regulating reservoir 56, while connecting between the pressure-increasing valve 53 and the

wheel cylinders

541, 542 in the conduit a2 and the pressure-regulating reservoir 56. The

pressure reducing valves

54 and 55 are solenoid valves that are opened and closed by an instruction from the 2 nd control unit 8, and are normally closed solenoid valves that are closed (blocked) in a non-energized state. The pressure reducing valve 54 is disposed in the pressure reducing line B on the

wheel cylinders

541 and 542 side. The pressure reducing valve 55 is disposed in the pressure reducing line B on the

wheel cylinders

541 and 542 side. The

pressure reducing valves

54, 55 are energized to be opened mainly during pressure reduction control, and the

wheel cylinders

541, 542 are communicated with the pressure regulating reservoir 56 via the pressure reducing conduit B. The pressure-adjusting reservoir 56 is a reservoir having a cylinder, a piston, and a force application member.

The circulation line C is a line connecting the pressure reducing line B (or the pressure regulating reservoir 56) and the differential pressure control valve 51 and the

pressure increasing valves

52 and 53 in the main line a (here, the branch point X). The pump 57 is provided in the circulation line C such that the discharge port is disposed on the branch point X side and the suction port is disposed on the pressure regulating reservoir 56 side. The pump 57 is a piston-type electric pump driven by a motor 90. The pump 57 flows the brake fluid from the pressure regulating reservoir 56 to the parent cylinder 1 side or the

wheel cylinders

541 and 542 side via the circulation line C.

The pump 57 is configured to repeat a discharge process of discharging the brake fluid and a suction process of sucking the brake fluid. That is, when the pump 57 is driven by the motor 90, the discharge process and the suction process are alternately repeated. During the discharge process, the brake fluid sucked from the pressure regulating reservoir 56 during the suction process is supplied to the branch point X. The motor 90 is energized and driven via a relay (not shown) by an instruction of the 2 nd control unit 8. The pump 57 and the motor 90 are also referred to as an electric pump.

The orifice portion 58 is a part of a closed shape (so-called orifice) provided between the pump 57 and the branch point X of the circulation line C. The damper section 59 is a damper (damper mechanism) connected to a portion of the circulation line C between the pump 57 and the orifice section 58. The damper unit 59 absorbs and discharges the brake fluid in accordance with the pulsation of the brake fluid in the circulation line C. The eyelet portion 58 and the damper portion 59 are referred to as a pulsation reducing mechanism that reduces (attenuates, absorbs) pulsation.

The auxiliary line D is a line connecting the pressure-adjusting hole 56a of the pressure-adjusting reservoir 56 and the upstream side of the differential pressure control valve 51 (or the master cylinder 1) in the main line a. The pressure regulating reservoir 56 is configured such that the valve hole 56b is closed as the inflow amount of brake fluid into the pressure regulating hole 56a increases due to the increase in stroke. The reservoir chamber 56c is formed on the pipe B, C side of the valve hole 56 b.

The brake fluid in the pressure regulating reservoir 56 or the master cylinder 1 is discharged to a portion (branch point X) between the differential pressure control valve 51 and the

booster valves

52 and 53 in the main line a through the circulation line C by driving the pump 57. Then, the wheel pressure is increased according to the control state of the differential pressure control valve 51 and the

pressure increase valves

52 and 53. In this way, the actuator 5 performs the pressurization control by the driving of the pump 57 and the control of various valves. That is, the actuator 5 is configured to be able to pressurize the wheel pressure. Further, a pressure sensor Y that detects a hydraulic pressure (line pressure) of a portion between the differential pressure control valve 51 of the main line a and the master cylinder 1 is provided. The pressure sensor Y transmits the detection result to the 1 st control unit 6 and the 2 nd control unit 8.

The 2 nd piping system 50b has the same configuration as the 1 st piping system 50a, and is a system for adjusting the hydraulic pressure of the

wheel cylinders

543, 544 of the front wheels Wfl, Wfr. The 2 nd piping system 50B includes a main piping Ab that corresponds to the main piping a and connects the piping 31 and the

wheel cylinders

543, 544, a differential pressure control valve 91 that corresponds to the differential pressure control valve 51,

pressure increase valves

92, 93 that correspond to the

pressure increase valves

52, 53, a pressure reduction piping Bb that corresponds to the pressure reduction piping B,

pressure reduction valves

94, 95 that correspond to the

pressure reduction valves

54, 55, a pressure regulation reservoir 96 that corresponds to the pressure regulation reservoir 56, a circulation piping Cb that corresponds to the circulation piping C, a pump 97 that corresponds to the pump 57, an auxiliary piping Db that corresponds to the auxiliary piping D, an orifice portion 58a that corresponds to the orifice portion 58, and a damper portion 59a that corresponds to the damper portion 59. The detailed configuration of the 2 nd piping system 50b can be described with reference to the 1 st piping system 50a, and therefore, the description thereof is omitted.

The pressure adjustment of the wheel pressure by the actuator 5 is performed by pressure-increasing control for directly supplying the main pressure to the wheel cylinders 541 to 544, holding control for closing the wheel cylinders 541 to 544, pressure-decreasing control for flowing the fluid in the wheel cylinders 541 to 544 to the pressure-adjusting reservoir 56, or pressure-increasing control for increasing the wheel pressure based on the closing of the differential pressure control valve 51 and the driving of the pump 57.

The 1 st control unit 6 and the 2 nd control unit 8 are Electronic Control Units (ECUs) including a CPU, a memory, and the like. The 1 st control unit 6 is an ECU that controls the servo pressure generator 4 based on a target wheel pressure (or a target deceleration), which is a target value of the wheel pressure. The 1 st control unit 6 performs pressurization control, pressure reduction control, or holding control on the servo pressure generating device 4 in accordance with the target wheel pressure. In the pressurization control, the pressure increasing valve 42 is opened, and the pressure reducing valve 41 is closed. In the pressure reduction control, the pressure increasing valve 42 is in a closed state, and the pressure reducing valve 41 is in an open state. In the holding control, the pressure increasing valve 42 and the pressure reducing valve 41 are in a closed state.

The 1 st control unit 6 is connected to various sensors such as a stroke sensor 71, pressure sensors Y, 25b, 26a, 15b5, and a wheel speed sensor 76. The 1 st control unit 6 acquires stroke information, line pressure information, reaction hydraulic pressure information, servo pressure information, wheel speed information, and the like from these sensors. The sensor and the 1 st control unit 6 are connected by a communication line (CAN) not shown.

The 2 nd control unit 8 is an ECU that executes control of the actuator 5 based on a target wheel pressure (or target deceleration), which is a target value of the wheel pressure. The 2 nd control unit 8 executes the pressure increasing control, the pressure reducing control, the holding control, or the pressure increasing control on the actuator 5 in accordance with the target wheel pressure as described above.

Here, each control state by the 2 nd control unit 8 will be described simply by taking control of the wheel cylinder 541 as an example, and in the pressure-increasing control, the differential pressure control valve 51 and the pressure-increasing valve 52 are in the open state, and the pressure-reducing valve 54 is in the closed state. In the pressure reduction control, the pressure increasing valve 52 is in a closed state, and the pressure reducing valve 54 is in an open state. In the holding control, the pressure increasing valve 52 and the pressure reducing valve 54 are closed. In the pressure control, the differential pressure control valve 51 is in a differential pressure state (closed state), the pressure increasing valve 52 is in an open state, the pressure reducing valve 54 is in a closed state, and the pump 57 is driven.

Various sensors such as the stroke sensor 71, the pressure sensors Y and 25b, and the wheel speed sensor 76 are connected to the 2 nd control unit 8. The 2 nd control unit 8 acquires stroke information, line pressure information, reaction hydraulic pressure information, wheel speed information, and the like from these sensors. The various sensors are connected to the 2 nd control unit 8 via communication lines not shown. The 2 nd control unit 8 executes the anti-slip control and the ABS control for the actuator 5 according to the situation and the request. The 2 nd control unit 8 is connected to the 1 st control unit 6 through a communication line so as to be able to communicate. In the first embodiment, the stroke sensor 71 and the 2 nd controller 8 are connected by a communication line Z1, the stroke sensor 71 and the 1 st controller 6 are connected by a communication line Z2, and the 2 nd controller 8 and the 1 st controller 6 are connected by a communication line Z3. For the other communication lines, the display in the figure is omitted.

To explain the cooperative control simply, the 1 st control unit 6 sets the target deceleration based on the stroke information, and transmits the target deceleration information (corresponding to "control information") to the 2 nd control unit 8 via the communication line Z3. The target line pressure and the target wheel pressure are determined according to the target deceleration. The 1 st control unit 6 and the 2 nd control unit 8 control the hydraulic pressure of the brake fluid so that the wheel pressure approaches the target wheel pressure (so that the deceleration approaches the target deceleration) by cooperative control. The 1 st control unit 6 calculates a target deceleration from the stroke to calculate a target line pressure, and the 2 nd control unit 8 calculates a target wheel pressure from the target deceleration, and sets a pressurization amount (control amount) from the detected line pressure and the target wheel pressure.

Here, the pressurizing mode of the upstream side pressurizing mechanism BF1 will be explained. A plurality of (here, 3) pressing modes are set in the upstream side pressing mechanism BF 1. The upstream side pressurizing mechanism BF1 is structurally set with a linear mode, a regulator mode, and a static pressure mode (a mode when the accumulator 431 fails) as pressurizing modes. The linear mode is a normal mode, and for example, in the pressurization control, the pressure increasing valve 42 is opened as described above to pressurize the servo pressure via the regulator 44, and the line pressure is pressurized.

The regulator mode is a mode that is executed mainly when the electrical system fails, and is a mode in which the 1 st control valve 22 is closed and the 1 st hydraulic chamber 1B is closed while the 2 nd control valve 23 is opened and the 2 nd hydraulic chamber 1C is communicated with the accumulator 171 in a non-energized state. Thereby, the lost motion disappears, and the reaction force hydraulic pressure becomes the atmospheric pressure, and the driver's operation of the brake pedal 10 becomes difficult to be transmitted to the master pistons 14, 15. That is, it becomes difficult to interlock the line pressure with the brake operation. In the regulator mode, brake fluid flows from the 2 nd master chamber 1E to the 2 nd introduction chamber 4E of the regulator 44 via the

pipe lines

31 and 311 and the port 4h in accordance with the brake operation. Thereby, the sub-piston 446 is pressed to press the control piston 445, the ball valve 442 is unseated, and the high pressure of the accumulator 431 is supplied to the servo chamber 1A, supporting the operation of the driver to pressurize the line pressure.

The static pressure mode is a mode in which the assist is impossible, for example, when the accumulator 431 fails, and is a mode in which the line pressure is pressurized simply by the operation of the driver. The pressurization mode of the upstream side pressurization mechanism BF1 can be said to be 2 of a linear mode in a normal state and a failure mode in which a regulator mode and a static pressure mode are combined. The pressurization mode may be a mode that is mechanically (automatically) selected in accordance with the state of the upstream side pressurization mechanism BF 1.

The plurality of pressurization modes are set so that the amounts of pressurization of the brake fluid with respect to the operation amount equivalent value corresponding to the operation amount of the brake pedal 10 are different from each other. The operation amount equivalent value is, for example, a stroke, a pedaling force, or an instruction amount (command value) in automatic operation. In the first embodiment, the pressurizing amounts with respect to the stroke of the 3 pressurizing modes are different from each other. The linear mode and the regulator mode can be switched by the 1 st control unit 6 in a normal state.

To summarize, the brake control device of the first embodiment is a device as follows: a1 st control unit 6 for controlling the servo pressure generating device 4 capable of pressurizing the brake fluid in one of a plurality of set pressurizing modes; a2 nd control unit 8 for controlling the actuator 5 provided separately from the upstream side pressurization mechanism BF1 and capable of pressurizing the brake fluid pressurized by the upstream side pressurization mechanism BF 1; and a communication line Z3 for mutually communicating control information between the 1 st control unit 6 and the 2 nd control unit 8, wherein the 1 st control unit 6 and the 2 nd control unit 8 perform cooperative control based on the control information. The 1 st control unit 6 and the 2 nd control unit 8 can command a plurality of control modes including pressurization control for pressurizing the brake fluid, holding control for holding the hydraulic pressure of the brake fluid, and decompression control for decompressing the brake fluid, respectively, in at least a normal state without failure.

(specific control at the time of communication interruption)

Here, specific control in the case where the transfer (communication) of the control information between the 1 st control unit 6 and the 2 nd control unit 8 is interrupted will be described. Most of the communication including the communication between the two control units 6 and 8 is configured by CAN. The detection of the communication interruption can be performed by a known method such as frame detection. Here, the 2 nd control unit 8 includes a normal control unit 81, a pattern estimation unit 82, and a specific control unit 83 as functions. The normal control unit 81 performs normal control (the above-described pressurization control and the like) in accordance with the target wheel pressure in a state where communication is not interrupted.

The mode estimating unit 82 estimates the current pressurization mode (current state) set in the upstream side pressurization mechanism BF1 when the transmission of the control information between the 1 st control unit 6 and the 2 nd control unit 8 is interrupted. Specifically, the pattern estimation unit 82 acquires the stroke information and the line pressure information, and estimates the current pressurizing pattern from the value of the line pressure (pressurizing amount) with respect to the value of the stroke (operation amount equivalent value).

As shown in fig. 4, the mode estimating unit 82 determines whether or not the value of the line pressure with respect to the value of the stroke is located in the 1 st region including the relationship (function) between the stroke and the line pressure in the linear mode in the map (determination map) of the relationship between the stroke and the line pressure. Outside the 1 st region, a2 nd region including a relation (function) between the stroke and the line pressure in the failure mode (regulator mode and static pressure mode) and a region in which the line pressure cannot be detected even in the assumption of the linear mode, that is, a region that cannot be determined (see a region boundary in fig. 4) are set.

If at least the current stroke and the current line pressure are known, the current region can be specified. The area determination (pattern estimation) by the pattern estimation unit 82 may be performed at a predetermined determination time from the time of communication interruption (interruption confirmation), or may be periodically performed a predetermined number of times. In addition, when the value of the stroke is in the area that cannot be determined, the pattern estimation unit 82 may interrupt the area determination, and perform the area determination again when the stroke has a value corresponding to the 1 st area. In the undeterminable region where the stroke is small, a large braking force is not required, and since this region is a portion of play, control in accordance with the pressurization mode is not particularly required.

The specific control unit 83 controls the actuator 5 based on the pressurization pattern estimated by the pattern estimation unit 82 in a state where the transmission of the control information is interrupted. The specification control unit 83 stores a preset excessive suppression map 83a (linear map) and a fail time map 83 b. Each map shows a relationship between the stroke and the amount of pressurization (target wheel pressure or target deceleration). The excessive pressure suppression map 83a is set such that the amount of pressure applied to the stroke is smaller than the failure time map 83 b. In the communication interrupted state, the specific control unit 83 controls the actuator 5 based on the excessive suppression map 83a when the pattern estimation unit 82 determines the current pressurizing pattern of the servo pressure generating device 4 to be the linear pattern.

On the other hand, in the communication interrupted state, when the mode estimating unit 82 determines that the current pressurizing mode of the servo pressure generating device 4 is the failure mode (regulator mode or static pressure mode), the specific control unit 83 controls the actuator 5 based on the failure time map 83 b. The excessive load suppression map 83a and the failure time map 83b according to the first embodiment are set to be different from the normal control of the target wheel pressure transmitted to the 2 nd control unit 8 based on the calculation of the 1 st control unit 6, which is performed when communication is possible (normal time).

The 2 nd control unit 8 is configured to maintain the control (specific control) by the specific control unit 83 until the brake state is released when the transmission of the control information is resumed when the specific control unit 83 controls the actuator 5 (i.e., during the specific control). In other words, when the communication is resumed (restored) and the information transmission is resumed when the specific control is executed, the 2 nd control unit 8 continues the control based on the pressure pattern estimated by the pattern estimation unit 82 (the control based on the excessive suppression map 83a or the failure time map 83 b) without being affected by the pressure pattern after restoration until the braking force becomes 0 (until the brake operation is released) and without being changed.

The flow of the specific control in the first embodiment will be described with reference to fig. 5. First, the 2 nd control unit 8 determines whether or not communication with the 1 st control unit 6 is interrupted (S101). When a communication interruption occurs (S101: YES), the mode estimating unit 82 estimates the current pressurizing mode of the upstream pressurizing mechanism BF1 based on the acquired stroke information and the line pressure information (S102). When the estimation result is the linear mode (yes in S103), the specific control unit 83 selects the excessive suppression map 83a as the control map, and controls the actuator 5 based on the excessive suppression map 83a (S104). That is, the specification control unit 83 sets a relatively low target wheel pressure for the stroke based on the excessive suppression map 83 a. Thereby, the braking force is suppressed excessively.

On the other hand, when the estimation result is the failure mode (no in S103), the specific control unit 83 selects the failure time map 83b as the control map, and controls the actuator 5 based on the failure time map 83b (S105). That is, the specification control unit 83 sets a relatively high target wheel pressure for the stroke on the basis of the failure time map 83 b. This makes it possible to compensate for the loss of braking force due to a failure. In this manner, the specific control unit 83 performs specific control in accordance with the pressurization mode of the upstream side pressurization mechanism BF1 by separately applying suppression of excessive braking force and securing of braking force according to the situation. When the communication is normal, the 2 nd control unit 8 is instructed of the target wheel pressure (target deceleration) from the 1 st control unit 6.

According to the first embodiment, when the information transmission between the two control units 6 and 8 is interrupted, the mode estimating unit 82 estimates the current pressurizing mode of the upstream pressurizing mechanism BF1, and the 2 nd control unit 8 controls the actuator 5 based on the estimated pressurizing mode. Therefore, control in accordance with the state of the upstream side pressurizing mechanism BF1 can be executed at an early stage, and as a result, an excessive braking force can be suppressed with high accuracy.

Further, since the mode estimating unit 82 estimates the pressurization mode based on the value of the line pressure with respect to the value of the stroke, that is, the relationship between the stroke and the line pressure, it is possible to estimate the state on the upstream side at the time when the braking operation by the driver is relatively small (that is, at the time when the stroke is relatively small). As described above, according to the first embodiment, the pressurization mode (state) of the upstream side pressurization mechanism BF1 can be estimated early when communication is interrupted, and the excessive braking force can be suppressed with high accuracy by switching the downstream side map (or gain or the like) early according to the pressurization mode. Namely, the braking feeling is improved.

In addition, in the first embodiment, when the specific control unit 83 performs communication restoration during the specific control, the specific control is maintained until the braking state is temporarily ended, and therefore, it is possible to suppress occurrence of discomfort of the driver due to a change in the map or the like during braking. When the braking operation is not performed, the control by the 2 nd control unit 8 is returned to the same control as that in the case of communication.

< second embodiment >

The 1 st control unit 6 of the second embodiment is configured to set the control mode to the hold control within a predetermined time from when the transmission of the control information between the 1 st control unit 6 and the 2 nd control unit 8 is interrupted, when the transmission of the control information between the 1 st control unit 6 and the 2 nd control unit 8 is interrupted during the braking. In other words, the brake control device 100 includes a fluid pressure holding unit that holds the fluid pressure (main pressure) of the brake fluid pressurized by the upstream pressurizing mechanism BF1 within a predetermined time from the time when the transmission of the control information between the 1 st control unit 6 and the 2 nd control unit 8 is interrupted during the braking when the transmission of the control information between the 1 st control unit 6 and the 2 nd control unit 8 is interrupted.

For example, when communication is interrupted during the pressurization control by the upstream side pressurization mechanism BF1 and the actuator 5, the 1 st control unit 6 changes the command to the upstream side pressurization mechanism BF1 from the pressurization control to the holding control within a predetermined time. Accordingly, even if the operation amount of the brake pedal 10 is reduced, the line pressure is temporarily maintained, so that the line pressure can be easily detected (that is, whether or not the line pressure is applied can be easily grasped), and the estimation of the pressure application mode can be easily performed with high accuracy. The other structure is the same as that of the first embodiment.

< third embodiment >

The mode estimating unit 82 of the third embodiment is configured to estimate the current pressurization mode set by the upstream pressurization mechanism BF1, based on the pressurization mode set by the upstream pressurization mechanism BF1 immediately before the interruption, when the transmission of the control information between the 1 st control unit 6 and the 2 nd control unit 8 is interrupted. That is, the pattern estimating unit 82 stores the information (for example, the current pressurization pattern) on the pressurization pattern of the upstream side pressurization mechanism BF1 received from the 1 st control unit 6 in a communicable state, and estimates the pressurization pattern stored immediately before the interruption (the latest information before the interruption) as the pressurization pattern after the interruption when the communication is interrupted. This enables simple and early pattern estimation. However, since the state of the upstream side pressing mechanism BF1 after the interruption is not observed in the third embodiment, it is preferable to adopt the first or second embodiment when it is desired to perform pattern estimation with high accuracy corresponding to a more practical situation.

(others)

The present invention is not limited to the above-described embodiments. For example, the estimation time (determination time) of the pattern estimation unit 82 may be set according to the magnitude of the brake operation (stroke or depression force). That is, the estimation time (determination time) can be shortened as the brake operation is larger, and early estimation can be facilitated. Further, when the communication is interrupted during the automatic operation, the mode estimating unit 82 may estimate the pressurizing mode based on the pressurizing instruction amount common to the 1 st control unit 6 and the line pressure detected by the pressure sensor Y, which are transmitted from the automatic operation ECU or the like to the 2 nd control unit 8. That is, even if communication during automatic operation is interrupted, the state of the upstream pressurizing mechanism BF1 can be determined based on the common pressurization instruction amount and the line pressure (upstream pressurization amount) generated by the upstream pressurizing mechanism BF 1.

In addition, when the communication is interrupted, the 1 st control unit 6 may set a rule for pressing the line pressure in a pulse form by the upstream side pressing mechanism BF1 without being affected by the brake operation, and the 2 nd control unit 8 may estimate the pressing mode by checking the state of the line pressure. In the linear mode, the line pressure varies due to the pulse-like pressurization, that is, the opening and closing of the pulse-like pressure increase valve 42. On the other hand, in the failure mode, the line pressure does not change due to an electrical failure of the pressure increasing valve 42 and/or a failure of the accumulator 431. The mode estimating unit 82 can estimate the current pressurization mode from a fluctuation in the line pressure with respect to a predetermined pressurization command (here, pulse-like pressurization) that is automatically applied to the upstream side pressurization mechanism BF1 without being affected by the brake operation at the time of communication interruption. The 1 st control unit 6 or a device other than the 1 st control unit 6 may perform a predetermined pressurization command. That is, the brake control device 100 may include a pressurization command unit that executes a predetermined pressurization command to the upstream pressurization mechanism BF1 when communication is interrupted.

In addition, the brake control device may be applied to a hybrid vehicle. In the hybrid vehicle, since the regeneration cooperative control based on the 2 pressurizing mechanisms BF1, 5 is executed, the cooperative control of the 1 st control unit 6 and the 2 nd control unit 8 is required, and the application of the present invention is effective. Further, even in a case other than the hybrid vehicle, by adjusting the braking force in the actuator 5 (downstream side pressurizing mechanism) capable of relatively easily performing fine adjustment of the wheel pressure, it is possible to create an appropriate braking feeling according to the situation. The present invention is also effective for a configuration using the downstream side pressurizing mechanism for creating the braking feeling.

In addition, when the 1 st control unit 6 is configured to switch between the linear mode and the regulator mode, the linear mode may be set to be selected as much as possible even when communication is interrupted if the communication is normal. For example, in the case where the value received by the 1 st control unit 6 is different from the value received by the 2 nd control unit 8 with respect to the detection value of the stroke sensor 71, the 1 st control unit 6 and the 2 nd control unit 8 cannot determine which value is believed to be better, and the 1 st control unit 6 can also purposefully switch the pressurizing mode of the upstream side pressurizing mechanism BF1 from the linear mode to the regulator mode. In such a configuration, the 1 st control unit 6 may be configured to prohibit the change of the pressurizing mode until the braking state is cancelled when the interruption of the communication is confirmed. This can suppress erroneous determination based on the variation in the pressurization mode.

Further, the control (specific control) corresponding to the estimated pressure mode is set to the control adapted to the state on the upstream side, as compared with the change of the map or the gain, and for example, in the case where the upstream side is the linear mode (normal), the pressure amount (target wheel pressure) with respect to the operation amount equivalent value (stroke, pedal force, or the like) may be smaller than in the case where the upstream side is the failure mode. The map set by the 2 nd control portion 8 is also referred to as a downstream deceleration request map. In addition, the regulator 44 may be not of a ball valve type but of a spool valve type. The upstream pressurizing mechanism is not limited to the one using the high-pressure source and the solenoid valve, and may be one using an electric supercharger (e.g., a system in which a regulator is operated by a motor). The hydraulic braking force generation device BF may be provided with a pedal force sensor that transmits the detection results to the 1 st control unit 6 and the 2 nd control unit 8. In addition, the pipe structure may be an X pipe. Further, the mode estimating unit 82 may be set to be able to further determine the regulator mode and the static pressure mode. This enables more precise (e.g., 3-map-based) specific control.

Claims

1. A brake control device includes: a1 st control unit that controls a1 st pressurizing mechanism capable of pressurizing a brake fluid in one of a plurality of set pressurizing modes; a2 nd control unit which is provided separately from the 1 st pressurizing mechanism and controls a2 nd pressurizing mechanism capable of pressurizing the brake fluid pressurized by the 1 st pressurizing mechanism; and a communication line for transmitting control information between the 1 st control unit and the 2 nd control unit, the 1 st control unit and the 2 nd control unit performing cooperative control based on the control information,

the brake control device includes a mode estimating unit configured to estimate a current pressurizing mode set in the 1 st pressurizing mechanism when transmission of the control information between the 1 st control unit and the 2 nd control unit is interrupted,

the 2 nd control unit includes a specific control unit that controls the 2 nd pressurizing mechanism based on the pressurizing pattern estimated by the pattern estimation unit in a state where transmission of the control information is interrupted.

2. The brake control apparatus according to claim 1,

the plurality of pressurization modes are set so that the amounts of pressurization of the brake fluid with respect to the operation amount equivalent value corresponding to the operation amount of the brake operation member are different from each other,

the mode estimating unit estimates the current pressurizing mode set in the 1 st pressurizing mechanism based on the pressurizing amount corresponding to the operation amount.

3. The brake control apparatus according to claim 2,

and a fluid pressure holding unit configured to hold the fluid pressure of the brake fluid pressurized by the 1 st pressurizing mechanism within a predetermined time from the interruption of the transmission of the control information between the 1 st control unit and the 2 nd control unit when the transmission of the control information between the 1 st control unit and the 2 nd control unit is interrupted during braking.

4. The brake control apparatus according to claim 1,

the mode estimating unit estimates the current pressure mode set in the 1 st pressure mechanism from the pressure mode set in the 1 st pressure mechanism immediately before the interruption when the transmission of the control information between the 1 st control unit and the 2 nd control unit is interrupted.

5. The brake control apparatus according to any one of claims 1 to 3,

the 2 nd control unit maintains the control by the specific control unit until the braking state is released when the transmission of the control information is resumed when the specific control unit controls the 2 nd pressurizing mechanism.